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AERONAUTICS BULLETIN NUMBER
UNIVERSITY OF ILLINOIS INSTITUTE OF AVIATION
Leslie A. Bryan, Ph.D., LL.B., Director James M. Hancock, A.B., Editor
UNIVERSITY OF ILLINOIS BULLETIN
Volume 52, Number 11; September, 1954. Published
seven times each month by the University of Illinois.
Entered as second-class matter December 11, 1912, at
the post office at Urbana, Illinois, under the Act of
August 24, 1912. Office of Publication, 207 Administra-
tion Building, Urbana, Illinois.
LESLIE A. BRYAN
Director, Institute of Aviation
University of Illinois
JESSE W. STONECIPHER
Chief Flight Instructor
University of Illinois
University of Illinois
SEP 3 1954
UftMSStY Of tUINOIS
PUBLISHED BY THE UNIVERSITY OF ILLINOIS, URBANA 1954
Table of Contents
THE APPROACH TO THE PROBLEM
INCIPIENT DANGEROUS FLIGHT CONDITIONS
The nature of the accidents
SUBJECTS SELECTED FOR THE CASE STUDIES
Basis of selection
THE AIRPLANE AND EQUIPMENT
Choice of the Beechcraft Bonanza
Equipment in the airplane
The loading condition
The landing gear problem
Flaps and cowl flaps
ANALYSIS OF THE TECHNIQUE
Basic concepts of the technique
CASE STUDY PROCEDURE
The Instruction Periods
The flight test
APPLICATION TO OTHER TYPES OF AIRPLANES
How to proceed
Specific airspeed recommendations
REPRESENTATIVE CASE RECORDS
The Aircraft Owners and Pilots Association Foundation, Inc., has long
been concerned with methods for reducing the number of civil aviation
light aircraft accidents caused by bad weather conditions. The Institute
of Aviation has had a continuing interest and has gained valuable experi-
ence in improved pilot training and in the problems of aircraft stability.
It was therefore logical that the two groups should join forces to devise
a curriculum which would train a noninstrument pilot to "get out of"
weather conditions into which he had flown inadvertently.
The AOPA Foundation, Inc., provided the funds for the experiment,
and the Institute then developed a curriculum which would train a non-
instrument pilot to retain control of his aircraft sufficiently well under
instrument weather conditions to enable him to fly back to noninstrument
conditions. The suggested curriculum is a "fly out" not a "fly through"
procedure. Since the curriculum accomplished its proposed purpose, it is
presented in detail in the second part of the text, together with comments
and suggestions to be used in teaching the procedure.
Both the Institute and the AOPA Foundation, Inc., believe that they
are rendering a public service to personal flying by making this procedure
available. The Institute would like to have amassed considerably more
data and to have spent more time on the project, but the results appeared
so conclusive that no purpose would have been served in the interests of
aviation safety by a further withholding of results.
The authors gratefully acknowledge the assistance, criticism, and
advice of the following people: Captain Paul A. Soderlind, Northwest
Orient Airlines; Dr. A. C. Williams, University of Illinois; Clifford P.
Marye, Flight Instructor, University of Illinois; Dr. August Raspet,
Mississippi State College; Francis B. Schaber, Shop Foreman, University
of Illinois; John P. Gaty, Vice-President, Beech Aircraft Corporation;
Bert A. Shields, Civil Aeronautics Board; and Kenneth R. Aldrich and
Carl VV. Clifford, Civil Aeronautics Administration.
The above persons have assisted in varying degrees. This acknowl-
edgmenl docs not necessarily imply endorsement by them of the experi-
ment or its results.
I hanks should also he extended to the subjects who participated in
these i .is'- studies and to the staff of the flight and the aircraft main-
tenance departments of the Institute of Aviation for their generous
donations ol time and lor their patience during the project.
In this monograph, as in all publications of the Institute, the authors
have had complete freedom to express their opinions, with the under-
tanding that the) will assume sole responsibility therefor.
funt 1954 Leslie a. bryan, Director
The Approach to the Problem
The instructions from the AOPA Foundation were, "Devise simple,
practical curriculum for special training program intended only to teach
pilot to keep plane upright if caught on instruments, make good enough
180-degree turn to get back to VFR weather, or get down through cloud
deck." These instructions were interpreted to mean that the final product
should be: (1) simple, (2) universally applicable to all light single-
engine airplanes, and (3) inexpensive and practical in terms of time and
A thorough search was made in current periodicals, books, and syllabi
for articles on simplified instrument flying technique. Numerous consul-
tations were held with expert instrument pilots, including the Institute
of Aviation staff, airline pilots, and instrument pilots on the staff of the
Aviation Psychology Laboratory at the University of Illinois. The result-
ing decision was to investigate a technique, not completely new, but
well described in an article by Paul A. Soderlind, entitled "Instrument
Lifesaver for the Contact Pilot."
Numerous flights were made in five different types of light aircraft,
during which the proposed technique was tested with entries made from
all attitudes and conditions of flight. Several weeks of flight testing, staff
consultations, and pretesting of three noninstrument pilots resulted in a
revised technique which seemed acceptable within the AOPA Foundation
directive. The system finally evolved differs in some respects from that
suggested by Soderlind, but the basic principles are the same.
A noninstrument pilot is an individual who does not hold a CAA
instrument rating or its equivalent. Instrument weather is that atmos-
pheric condition in which the pilot has no visual points of reference
outside the aircraft. Most noninstrument pilots can be placed in one of
the three following categories : ( 1 ) the noninstrument pilot who knows
he could not fly instruments and takes every precaution to avoid instru-
ment weather; (2) the noninstrument pilot who "knows" he could not
fly instruments, takes every precaution to avoid instrument weather, but
believes his knowledge and experience would enable him, if caught, to fly
out of the instrument weather; (3) the noninstrument pilot who believes,
primarily through ignorance of the problems involved, he could fly
through instrument weather.
The syllabus evolved for teaching the technique is aimed directly at
these three types of noninstrument pilots.
Incipient Dangerous Flight Conditions
This study is concerned with serious, near-fatal, and fatal accidents
which occur because pilots, untrained in instrument flying, attempt to fly
under actual instrument conditions.
Such accidents (1) occur with the greatest frequency in single-engine
airplanes of less than 5,000 pounds gross weight, (2) happen in airplanes
which are equipped with either partial or full instrument panels, (3) oc-
cur with the greatest frequency to noninstrument-rated pilots, (4) happen
most often to pilots who have had no previous experience under either
actual or simulated instrument conditions, and (5) occur in marginal
or sub-marginal weather conditions.
All authorities agree that nonprofessional pilots, untrained in instru-
ment flying techniques, place too much emphasis on instrument-flying
equipment and too little emphasis on proper training in the use of instru-
ments. Experts are at a complete loss to explain the enigma of a business-
tnan pilot who invests several thousands of dollars in an airplane with a
full instrument panel, radio equipment, and even an auto-pilot, but who
apparently unwilling to invest additional funds or the time to obtain
in trumenl experience which would enable him to make the safest and
mo i < ffif ient use of his airplane.
A majority of the experts expressed the belief that all student pilots
should be thoroughly acquainted with the problems of instrument flying
through an actual experience under simulated instrument flight condi-
tions, similar to Period 1 in "The 180-Degree Turn Syllabus," prior to
authorization for their first solo cross-country flight. 1
It seems true also that a large majority of the nonprofessional pilots,
untrained in instrument flying, entertain a basic misconception about the
nature of instrument flying. This misconception centers around the idea
that instrument flying can be learned through a series of flights under
progressively lower visibilities, where the technique employed is gradually
modified from that used under CAVU conditions to that employed under
instrument conditions. In addition, it was felt that many of these pilots
mistakenly believe that the techniques involved in visual night flying
were closely related to instrument flying. However, the difference be-
tween visual flying and instrument flying is neither the degree of visibility
nor the number of reference points available to the pilot; instrument
flying is denoted by the reference points used for controlling the attitude
of the airplane which are located inside not outside the airplane. It is
not how much the pilot sees, but where he sees it. 2
THE NATURE OF ACCIDENTS
The type of accidents under consideration usually take one of two
forms, either the so-called "graveyard spiral" or the "roller coaster."
The "graveyard spiral" is the most prevalent, and it is abetted by the
lack of positive spiral stability in present-day aircraft. The following
series of events are involved: (1) shortly after entering instrument con-
ditions the airplane starts to turn, 3 (2) the pilot fails to note the turn or,
if he does note it, fails to correct usually because of vertigo, (3) the bank
increases causing the nose to cant downward which results in an increase
in airspeed, (4) the pilot recognizes the increased airspeed and applies
corrective measures in the form of increased back-pressure on the yoke
1 It is interesting to note that the twenty subjects in this case study were unani-
mous on this point after they had completed Period 1. This procedure has been
standard practice at the University of Illinois for a number of years with beginning
2 An experiment conducted by the Aviation Psychology Laboratory at the Uni-
versity of Illinois indicated that a relatively inexperienced pilot can do a reason-
ably safe job of piloting an airplane with only an extremely limited view outside
3 This may be caused by any number of events - — the pilot, a gust, imperfect
lateral balance, etc.
or stick, (5) the increased back-pressure tightens the turn, the nose cants
downward, the airspeed increases, and more back-pressure is applied in
an effort to slow up the airspeed.
To an observer riding along, it appears that the pilot rolls gently into
an increasingly steeper bank and allows the degree of dive to increase
simultaneously. Under these conditions a very short time is required
for the airplane to go from normal flight into a diving spiral, a 60- to
70-degree bank, and the red-line airspeed; the cleaner the airplane, the
less time required for this to happen.
The second variety, appropriately called the "roller coaster," occurs
when the pilot fixes his attention on the airspeed indicator and/or the
altimeter. The pilot is inclined to rely on these two instruments in an
unfamiliar situation since they are the instruments most frequently used
under visual conditions. However, the pilot fails — or is unaware of the
necessity — to allow for momentum lag. In an effort to make the indi-
cators show the desired reading, he puts the airplane through a series
of increasingly violent climbs and dives. Unfortunately, the "lagging"
instruments give the impression that the airplane is at the top of a climb
when it is actually in a diving attitude, or vice versa. The final result is
usually a structural failure due to excessive G loads.
For the purpose of this study a Beechcraft Bonanza C-35 was selected.
On the basis of preliminary testing it was decided that for the purpose
of this study an incipient dangerous flight condition and/or attitude had
been reached when the subject pilot allowed any one or any combination
of the following situations to develop: (1) a stall, either normal or
accelerated; (2) a bank in excess of a medium bank (45 degrees) ; (3) a
speed in excess of normal fast cruise; (4) obvious and prolonged loss of
either altitude or directional orientation.
Normal equipment on the aircraft used enabled the instructor to take
absolute measurements of the first three situations, and it was agreed that
the fourth must necessarily be an arbitrary decision based on the circum-
stam es existing at the time.
Subjects Selected for the Case Studies
Three private pilots, none of whom had had previous instrument
flight experience under either simulated or actual conditions, were
selected as pretest subjects. These subjects were put through an experi-
mental syllabus based on the experience gained from the preliminary
flights. The results thus obtained were encouraging and the test syllabus
was modified in accordance with the findings on the pretest subjects.
Primary modifications were (1) a standardized recording sheet, (2) the
addition of the present flight number 1, and (3) the addition of a "free
trial" experience in the final period.
Pretest subjects are not included in the tables showing the results of
the case studies.
BASES OF SELECTION
The same basic criterion used in selecting the airplane, that of testing
the technique under the most adverse circumstances possible, was adopted
in selecting the subjects.
The bases of selection for the volunteer case study subjects were that
they should ( 1 ) be representative as to chronological age — the group
selected ranged in age from 19 to 60 years, (2) have had no previous
instrument experience under either simulated or actual conditions,
(3) have had a minimum of experience in the Beechcraft Bonanza, and
(4) be as representative as possible with respect to actual logged flight
Twenty subjects were selected on the basis of the above criteria.
Table 1 shows the age, pilot certificate, airplanes flown, and logged
flight experience of the subjects used in the case study.
The Airplane and Equipment
CHOICE OF THE BEECHCRAFT BONANZA
The Beechcraft Bonanza C-35 was selected for use in these case studies
upon the basis of the preliminary flight testing which indicated that
the technique would be most difficult to accomplish in the Bonanza. The
Bonanza was also considered representative of the most complex light
single-engine airplane normally flown by the nonprofessional, noninstru-
ment pilot. In addition, it was desirable to use an airplane with which the
subject had had the least amount of experience. In short, the assumption
was made that if the subjects, none of whom had soloed a Bonanza,
could master the technique in this airplane, they could master it in any
single-engine airplane under 3,000 pounds gross weight.
EQUIPMENT IN THE AIRPLANE
In the experiment it was decided to use only those instruments and
equipment specified in Civil Air Regulation 43.30 for visual flight rules,
plus a turn indicator. Therefore in equipping a standard Beechcraft G-35
for these case studies, the artificial horizon, the directional gyro, and the
rate-of-climb indicators were covered. Amber plexiglass covered the wind-
shield and the side glasses. The subject pilot was equipped with nonpolar-
izing blue goggles to simulate instrument flight conditions. The amber-blue
combination reduced the cockpit visibility to an undesirable degree, how-
ever, and it was necessary to install additional cabin lights — one focused
on the compass and the second spotted on the instrument panel. Even
with the additional lights, most subjects found it difficult to read the
trim-tab indicator. As a consequence, the instructor carried a flashlight
for spotting this indicator when it was necessary for the subject to read it.
Before each flight, the instructor checked the blue goggles and the amber
windshield for possible spots through which the subject might have
THE LOADING CONDITION
For the purposes of the case studies, the airplane was loaded in the
most rearward allowable center of gravity (e.g.) condition. 6 The airplane
was loaded to maximum gross weight, 2700 pounds, with one subject and
one flight instructor occupying the front seats, a full load of fuel and oil,
sandbags weighing 340 pounds in the rear seat, and a 50-pound sandbag
in the baggage compartment. This gave a rearward e.g. of +84.16 aft of
datum for take-off; the allowable limit was calculated as +84.4.
All flights were limited to a maximum of 80-minutes duration during
which time, because of fuel consumed, the gross weight became 2620
pounds, and the calculated e.g. position was +84.4 aft of datum. The
allowable e.g. limit for a gross weight of 2620 pounds was calculated as
being +84.43 aft of datum.
Frequently a second flight instructor occupied the right rear seat. In
this case, an amount of sand equal to the weight of the instructor was
removed from the rear seat.
THE LANDING GEAR PROBLEM
In initial tests of the technique, the landing gear was not lowered
until the speed had been reduced to that recommended by the airplane
6 The complete weight and balance form in this instance is reproduced in the
Handbook (not above 125 m.p.h.). This necessitated lowering the gear
as one of the final steps, thereby losing the advantage of using extended
gear to slow the airplane. It was subsequently learned that the Bonanza
gear could be lowered, without danger, at cruising speed. This was done
throughout the complete experiment.
FLAPS AND COWL FLAPS
During the preliminary testing of the technique and the pretest sub-
ject flights, it was found that full flaps on the Bonanza resulted in an
extreme forward (nose-down) pitching moment. With full flaps and the
airplane loaded in the rearward e.g. condition almost full nose-up trim
tab was required to obtain the desired airspeed of 95 m.p.h.
The wide range of trim-tab travel required to compensate for full
flaps resulted in a greater number of phugoid 7 oscillations with greater
extremes in attitude at the top and bottom of the oscillation. When the
oscillations had ceased there was no apparent improvement in the longi-
tudinal stability of the airplane.
Because the use of flaps involved two undesirable effects — one more
task for the pilot to perform and a greater number of and wider extremes
in oscillations — it was decided to perform the entire project without
Experiences with the Bonanza indicate that the use of flaps by non-
instrument pilots, when encountering instrument weather conditions
unexpectedly, is not to be recommended; such use of flaps complicates
rather than simplifies the task of controlling the airplane.
The cowl flaps and carburetor heat on the Bonanza were omitted in
planning the procedure, since opening and closing them further com-
plicated matters for the subject. It was decided that undue heating and/
or cooling, except under rare circumstances, would not be experienced
to a degree which would result in a dangerous flight condition.
Analysis of the Technique
BASIC CONCEPTS OF THE TECHNIQUE
I he noninstrument pilot encountering either actual or simulated in-
strument flight conditions lor the first time usually overcontrols the
Hereaftei when oscillation is used it will refer to phugoid oscillation, i.e., a
long period oscillation characteristic of the disturbed longitudinal motion of an
;iii plan< .
airplane. He is also likely to fix his attention on one instrument and
ignore the others. Hence, the technique described below is intended to
( 1 ) utilize the inherent stability of the airplane as a partial solution to
the complexity of the problem, (2) reduce the possibility of overcontrol,
(3) minimize the control required to obtain the desired result, (4) limit
the division of attention on the part of the pilot, (5) reduce the possi-
bility of structural damage through excess speed and the potential attend-
ant G loads, and (6) teach the pilot the "key" instruments upon which
he should concentrate his attention.
The technique is mechanical and requires a minimum of practice and
skill. We do not consider the use of the technique to be instrument flying
in the usual sense. For the twenty case studies reported, the steps were
typed on a small card which was affixed to the instrument panel. Thus
it could be read as a check-list by the pilot.
Immediately upon entering instrument weather the pilot must com-
plete, in order, the following steps:
Center the Turn Needle. This is not listed as a specific step be-
cause it is a continuing task and requires more attention and skill
than any of the steps. The needle should be centered and kept
centered by alternating the attention between the progressive
steps and the needle. Centering is done entirely with the rudder.
( 1 ) Hands Off. This eliminates the possibility of overcontrolling the
elevator and places reliance upon the inherent angle of attack
(speed seeking or pitch) stability of the airplane. The highest
speed obtained after the hands are removed will be that for which
the airplane is trimmed, provided the airplane is not allowed to
enter a spiral dive.
(2) Lower the Gear. This step is accomplished at cruising speed. The
added drag will materially reduce the possibility of excessive
(3) Reduce Power. Power should be reduced to a position somewhat
8 Mr. John P. Gaty, Vice-President and General Manager of Beech Aircraft,
Inc., states, "We feel that it would be safe to extend the [Bonanza] landing gear as
long as the airspeed indicator is in the green sector, which is up to 160 m.p.h.
indicated. Probably in emergency conditions, it might be reasonable to extend the
landing gear as long as the airspeed is in the yellow sector, which would top
(4) Set Trim Tab. The trim tab is rolled to a predetermined and
premarked position which will give the desired slow flight speed
— in the case of the Bonanza, 95 m.p.h. — with the airplane
loaded in the most rearward allowable e.g. position. The speed
and the trim-tab setting required to obtain the speed is deter-
mined experimentally and under visual flight conditions. 9
(5) Adjust Prop Pitch and Power. The prop pitch should be in the
full high r.p.m. (low-pitch) position. The power (either tachom-
eter or manifold pressure) should be set to a predetermined,
premarked position. The power required is to be determined
experimentally and under visual conditions after the trim-tab
setting is found for the desired speed. When the airplane is
trimmed for the slow speed (Bonanza, 95 m.p.h.) and the prep
is in high r.p.m., the power is then adjusted to the amount
required to maintain altitude exactly. In the Bonanza this is
approximately 17 inches with the prop in high r.p.m.
The foregoing steps should be accomplished positively, without hesi-
tation or waiting, and in the order listed. The completed steps will cause
the airplane to go through a series of oscillations. The number of oscilla-
tions and the severity — extremes in longitudinal pitch — will be directly
affected by the interval between steps. Once the steps are started they
should be completed without pausing between steps. Pausing or delaying
between steps will result in a variety of unusual attitudes, depending
upon where the pause occurs. On the other hand, if the steps are com-
pleted without hesitation, the transition from cruising to slow flight will
be accomplished with the minimum of oscillations.
(6) Note Compass Heading. The heading may or may not be the
heading of original entry. However, the pilot should determine the
reciprocal of the original heading which led him into the instru-
(7) Turn with Rudder. The turn needle should be moved to a
three-fourths standard rate turn position using the rudder only,
and the pilot should concentrate on maintaining a constant rate
of turn, i.e., keeping the needle as nearly on the three-fourths
standard position as possible. The three-fourths standard rate
turn is used rather than the standard rate because of the shal-
' A table ol recommended speeds for various light single-engine airplanes is
included on page 22. Any predetermined speed can be set up. The recommended
Ipeedfl represent the authors' opinions as bring the best, all things considered.
lower bank required and the faet that acceleration (change in
rate of turn) is less likely.
(8) Roll Out with Lead or Lag. This refers to the "lead" or "lag"
required to compensate for inherent compass errors including dip,
northerly turning error, and acceleration error.
(9) Center the Needle and Note the Heading. If the desired heading
appears after the compass settles down, the problem is one of
keeping the needle centered until visual conditions reappear. If
the desired heading is missed by more than 30 degrees, appro-
priate corrections should be made. If visual contact is not made
within a few minutes, the next step should be started immediately.
(10) Reduce Power. The power should be reduced a predetermined
amount to give a 400- to 500-f.p.m. rate of descent. This probably
will mean a reduction of 5 to 6 inches of manifold pressure or
300 to 500 r.p.m. in the case of fixed-pitch propellers. 10
Of the foregoing steps, psychologically the most difficult one to accom-
plish is the first, Hands Off, and in many respects it is the most important
one. The step requiring the greatest degree of skill and practice is con-
trolling the needle through rudder action. The most novel step to non-
professional pilots is that of using the compass to indicate completion of
Case Study Procedure
The twenty subjects selected were given the course of instruction and
the tests outlined in detail in the syllabus. In order to eliminate instructor
differences, only one flight instructor was used for the twenty cases
studied; occasionally, a second flight instructor occupied the right rear
seat for purposes of observing or recording the performance of the subject.
Accurate records of flight time, simulated instrument time, and per-
formances were kept by the instructor. The tracks were diagrammed
wherever practical and/or applicable. The records on a representative
case are reproduced on page 53.
It will be noted that the syllabus includes six periods, each of which
consists of approximately 20 minutes of discussion and 40 minutes of
10 If, in the exceptional case, it is desired to climb, increasing the manifold
pressure 5 to 6 inches, or 300 to 500 r.p.m. in the case of fixed-pitch propellers,
will accomplish the desired purpose.
flight. The first and last periods are devoted entirely to testing; the four
intermediate periods are devoted to teaching.
The purpose of the first period was twofold — to acquire some indica-
tion of the subject's ability to control the airplane under simulated instru-
ment eonditions, against which his final flight performance could be
measured, and to provide the student with a subjective appraisal of his
own ability as an instrument pilot.
Standard altitude for beginning the first simulated instrument flight
was 2500 feet above mean sea level (1750 feet actual). Higher altitudes
were used during the first flights of the first five subjects; a change was
made to the lower altitude because the potential disaster was more
apparent to the subject if the ground was literally "staring him in the
face" when he raised his goggles.
Nineteen subjects placed the airplane in a "graveyard spiral" on the
first attempt to fly by instruments. The twentieth subject pulled the
airplane into a whip-stall attitude. Minimum time to reach the incipient
dangerous attitude was 20 seconds; maximum time was 8 minutes. These
results reaffirm the generally accepted premise that the spiral instability
of present-day light aircraft, together with the pilot's lack of instrument
flight experience, is a major factor contributing to fatal accidents.
The flight instructor recovered from the "graveyard spiral" cases at
the 185 m.p.h. indicated. This speed was selected because the airplane
Time Elapsed 11
Time Elapsed 11
The average time was 178 seconds or 2 seconds short of 3 minutes.
" I Ins time is included in the subject's simulated instrument time
was in a bank and dive sufficiently steep so that the airspeed reached
200 m.p.h. by the time recovery had been effected. The recovery from the
whip-stall attitude was effected before the actual stall occurred. In all
cases the subjects were instructed to remove the goggles before the
instructor started the recovery, so that the subject could definitely
observe the attitude of the airplane before the recovery was effected. The
first attempt to control the airplane solely by reference to instruments
proved a startling experience to all pilots tested regardless of the amount
of previous flight experience under visual conditions.
Table II shows the time required by each subject to reach an incipient
dangerous flight condition. The time shown is the total time from the
point the goggles were placed over the subject's eyes to the moment he
was instructed to remove the goggles and observe the dangerous attitude
of the airplane.
THE INSTRUCTION PERIODS
Periods 2, 3, 4, and 5 in the syllabus arc devoted entirely to teaching
the technique. In general, the first five steps were introduced in Period 2,
the second five steps in Period 3, and Periods 4 and 5 were devoted to
Eighteen of the subjects were considered proficient at the end of
Period 5 and were given the flight test described under Period 6. The
two remaining subjects were given an extra period of practice (Period
5X) and were then given the test indicated in Period 6.
Table III shows the simulated instrument time and the total flying
time accumulated by each subject during the case study.
THE FLIGHT TEST
Period 6 was devoted to testing the results of the instruction which
the subject received during Periods 2, 3, 4, and 5.
The three phases of the flight test, briefly described, were:
Phase 1 — The subject was given a series of three problems, each
one involving performance of the complete task of encountering in-
strument weather, making the transition from cruise to slow flight,
making a 180-degree turn, and executing a controlled descent. No
assistance was given by the instructor except such information as
would have been available to the subject on the radio, i.e., weather
reports. The subject was graded primarily on his ability to complete
the entire problem without approaching an incipient dangerous flight
TABLE 1 1 1
Total Flight Time
Two subjects were given one extra flight (5X).
condition and to complete the 180-degree turn within 30 degrees of
the desired track.
Results of Phase 1 — The twenty subjects were given three trials
each, a total of sixty trials. Fifty-nine of the sixty trials were com-
pletely successful. Subject 17, on the first of his three trials, failed to in-
clude step 5 which involved adjusting the prop pitch and power to the
marked position for maintaining altitude. The omission of step 5
resulted in a steady loss of altitude which was continued during the
180-degree turn and after the airplane was established on a reciprocal
course. The instructor called the attention of the subject to the loss of
altitude at approximately 100 feet above ground. Under the definition
oi an incipienl dangerous flight condition this trial was unsuccessful.
On the next two trials this subject's performances were successful. 12
Phase 2 — Upon completion of the three simulated problems, each
subject was informed that he had completed the course and that he
had met the required standards. The subject was then invited to test
any theory or idea which he believed might be a better solution to
the problem. There were two reasons for including this in the final
flight: (1) the investigators were genuinely interested in any sugges-
tions which the subjects might have to offer, and (2) it provided the
subject with an opportunity to try out his own "pet" ideas on the
Results of Phase 2 — Every subject accepted the invitation to a
fourth trial. Only two of them, however, attempted new variations
beyond those which they had been taught during Periods 2, 3, 4, and
5. In these two cases the subjects expressed the idea that the oscillations
which occurred during the performance of steps 1 through 5 could be
dampened by the pilot if he were allowed to keep his hands on the
control yoke. In both cases, upon trial, the attempted dampening was
out of phase with the proper correction and resulted in even more
extreme oscillations. The two subjects realized this fact almost at once
and consequently both subjects immediately released the yoke and
continued through the remainder of the steps with "Hands Off."
Phase 3 — This phase of the flight test was not included in the
study of the twenty cases but was added to the experiment in an effort
to satisfy one of the most consistent objections raised by pilots inquir-
ing about the project. Their objection was that successful completion
of the 180-degree course might encourage the subjects to use this
system to fly through instrument weather rather than to get out of
Briefly, this phase involves asking the subject to demonstrate his
ability to fly under simulated instrument conditions to a specific geo-
graphic location. This request is realistic since this objective can be
accomplished if the pilot is a qualified instrument pilot and if the
geographic location is equipped with appropriate radio navigation
Noninstrument and 180-degree turn pilots will not be able to
accomplish Phase 3. This test will effectively demonstrate to them,
12 Under actual instrument weather conditions the pilot would probably have
"broken out" and would then have been able to continue visually. Even in zero-
zero conditions there was doubt as to whether a fatality would have resulted since
the aircraft speed was low, and the rate of descent was slow and under control.
however, that instrument flying, as distinguished from the 180-degree
turn emergency system, involves considerably more knowledge and
skill than that which is offered in the 180-degree turn syllabus.
Application to Other Types of Airplanes
Tests of the technique were tried in a variety of light, single-engine
airplanes. Analysis of these trials proved that the technique can easily be
adapted to most airplanes now available to the civil, nonprofessional pilot.
Other than on the Beechcraft Bonanza, the technique was not employed
on airplanes with retractable gear or with controllable-pitch propeller,
nor on any so-called two-control, or rudderless, airplanes.
HOW TO PROCEED
The general order of the steps for tailoring the technique to other
light aircraft will not vary except in those cases where the airplane does
not have retractable gear or a controllable propeller. In those cases, the
appropriate steps are (1) hands off, (2) adjust power, and (3) adjust
trim. In all cases the net result of the tailoring is to find the trim-tab
position and the power setting. These are found as follows :
(1) Determine the loading condition. This step involves a decision as
to the most frequently used loading condition of the airplane.
This may be solo with no baggage, with one or with two pas-
sengers, or with a maximum gross load. The term "most fre-
quently used loading condition" is important here; if there is
any doubt as to the load most frequently carried, the maximum
load should be used.
(2) Find the best airspeed. This step is for the purpose of determining
the best airspeed for the particular airplane. The best airspeed
will be near the recommended approach speed. It should be slow
enough to reduce the possibility of excessive G loads, but not so
slow that the roll (lateral movements) of the airplane cannot be
readily controlled through the rudder. 13 At a safe altitude,
properly loaded, the throttle should be reduced below the cruising
In some instances it was found that 5 m.p.h made a great deal of difference
in the roll response obtained the Cessna 170, for example, was very slow to
" I""" 1 to .i rudder roll a1 7 r > m.p.h. but at 80 m.p.h. excellent response was
position. 14 The airplane should be slowly trimmed to fly hands-off
at the desired slow speed. Once the speed is trimmed in, several
unusual attitudes should be attempted — hands still off the yoke
— and special attention devoted to the response obtained with
rudder only. The severest trial is to test roll recovery from a bank
in excess of 70 degrees. If positive response is obtained the air-
speed is suitable. If the airplane has retractable gear, it is advis-
able to have it in the "down" position during the foregoing trials.
(3) Mark the trim-tab position. This mark should be made only after
several trials have definitely proved that rolling the trim tab to
this point will always result in the desired speed after the airplane
has completed two or three oscillations. These trials must also be
made with hands off the yoke. Once the correct trim-tab position
is found it should be plainly marked.
(4) Find the power setting. This step is to determine the exact power
setting required to maintain altitude at the desired speed. If the
airplane has a controllable propeller, it should be set in the low
pitch (high r.p.m.) position. The altimeter and rate of climb, if
one is installed, should be observed while the throttle is slowly
adjusted to the position for maintaining altitude. Do not be
satisfied with a power setting which will almost hold the altitude.
The airplane should be allowed to fly for several minutes, hands
off, with fine adjustment made in the throttle setting to bring the
altitude into balance. Once the power position, or throttle setting,
is established it should be prominently marked. A piece of tape
cut to the size and shape of the indicator hand and pasted on the
dial of the tachometer or manifold pressure gauge makes a suit-
(5) Check settings. This is a complete test for the accuracy and
reliability of the speed, trim, and power determined in the pre-
ceding paragraphs. The airplane should be placed in normal
cruising attitude with cruising power and trim, and the speed
allowed to come up to normal cruise. The following steps should
be completed without hesitation between steps: (a) hands should
be taken off the stick or yoke, (b) gear lowered, 15 (c) power re-
14 Exact setting is not important so long as the power is below cruising but
15 Any airplane other than the Beechcraft Bonanza should be checked with the
manufacturer to determine whether the gear can be lowered safely at cruising
duced, (d) trim tab set, and (e) pitch and power adjusted to
setting. The airplane will go through a series of two or three
oscillations. When the oscillations are completed the airplane
should have settled down to the predetermined airspeed with
altitude maintained after a gain of one or two hundred feet.
One complete check of the settings is not satisfactory. Additional trials
will result in finding a "timing" or "pace" which will create a smooth
transition from cruise to slow flight conditions. In the Bonanza there is
a "pace" which gives a smooth transition with only one oscillation. A
small amount of practice and experimentation will establish the "pace"
for the particular airplane.
SPECIFIC AIRSPEED RECOMMENDATIONS
The airspeeds recommended for light aircraft tested during the experi-
ments are: 16
Aeronca 7AC 65 m.p.h.
Piper Vagabond 70 m.p.h.
Cessna 120 and 140 75 m.p.h.
Piper Tri-Pacer 80 m.p.h.
Cessna 170 80 m.p.h.
Stinson 150 85 m.p.h.
Bonanza 95 m.p.h.
No unusual or extraordinary flight characteristics were experienced in
any of the foregoing airplanes.
The technique will require considerable modification in order to be
applied to a two-control airplane such as the Ercoupe. The technique
has not been tested in either a Navion or a Bellanca, but it is believed,
on the basis of previous flight experience with these airplanes, that the
technique could be adapted to them.
sp< ed. Mr. D. H. Williams, Project Engineer of the Ryan Aeronautical Company,
says of the Navion, "As you know, the Navion airplane is placarded against lower-
ing the gear and flaps above 100 m.p.h. Although 100 m.p.h. is the C.A.A. ap-
proved speed, we Bight test all production airplanes at 120 m.p.h. Operation above
this speed is not recommended on landing gears equipped with fairings. . . . The
older Navion airplanes, not equipped with fairings, were qualified at a speed of
"These speeds are approximately twice normal stalling speeds. They were
selected as representing the speeds which, in addition to positive control, represent
the most satisfactory speeds in turbulence, which might cause unexpected stall
problems, and which, at the same time, provide the optimum protection against
ive G loads on the aircraft structure.
The following conclusions were reached upon examination of the
twenty cases studied:
(1) Pilots who have had no previous experience with instrument
flying cannot expect to survive their first experience under actual
instrument conditions, except by mere chance.
(2) The 180-degree turn curriculum, properly organized and directed,
will materially increase the chances of surviving the first experi-
ence with unexpected instrument weather conditions.
PERIOD 1 25
Preflight discussion 25
Postflight discussion 28
PERIOD 2 30
Preflight discussion 30
Airspeed and altitude 32
What instruments 33
Mechanics plus technique 33
Rudder control 34
Preflight discussion continued 34
General comments 36
Controlling the turn indicator 39
PERIOD 3 40
Preflight discussion 40
Magnetic compass 41
Compass turns 42
Proper degree of bank 43
Making small corrections of direction 43
Two don'ts 45
Lead or lag 45
PERIODS 4 & 5 48
Preflight discussion 48
PERIOD 6 49
Preflight discussion 49
Postflight discussion 51
REPRESENTATIVE CASE RECORDS 53
Instructor Guide to the 1 80-Degree Turn Procedure
The 180-degree curriculum 17 consists of six one-hour periods. Each
period is divided into preflight discussion, the actual flight, and post-
flight discussion. The preflight discussion prepares the student for the
flight. The flight section includes a brief description of what should be
accomplished in the air. The postflight discussion emphasizes the results
of the flight period. It is the intent of this syllabus to suggest a method
for teaching the 180-degree turn procedure.
The instructor will need to be extremely selective about "what" and
"how much" information he gives the student. He should make the
student conscious of the problems of instrument flight, teach him how
to turn out of instrument flight conditions successfully, and encourage
him to continue his education and training as a safe and qualified
In the following syllabus the aircraft used is a Beechcraft Bonanza.
For purposes of realism both the preflight and postflight discussions are
in the first person and are suggested explanations which instructors may
Purpose: To demonstrate to the "contact" pilot that he cannot control
his aircraft under instrument flight conditions.
PREFLIGHT DISCUSSION: APPROXIMATELY 10 MINUTES
"The average pilot uses visual references on the ground to tell him
what the airplane is doing. When he loses sight of the ground, or any
outside cue he may be using to control the attitude, he is unable to
control the aircraft, i.e., he no longer knows whether he is turning,
going up or down, or flying straight and level. He cannot control the
plane from the information given him by his physical sensations which,
more often than not, give false information. In other words, the 'seat of
the pants' is not reliable. A pilot cannot fly in the clouds without
knowledge of instrument flying.
"In an effort to decrease the appalling percentage of fatal light air-
craft accidents in civil aviation due to pilots attempting to fly in instru-
ment weather conditions without the necessary skill, the University of
Illinois was commissioned by the AOPA Foundation, Inc., to find a
17 Also spoken of as the "emergency turn" or "self-saving" curriculum.
18 If the student owns his airplane, he should take his instruction in it after
the instructor has established the procedure for that aircraft.
simple solution whereby the average 'contact' pilot could control the
aircraft well enough to 'get out of bad weather and return to a point
where he could see the ground. In an effort to find a way to do this,
the University of Illinois has devised a six-period curriculum.
"In the first period you will (1) familiarize yourself with the plane
and (2) have presented to you the basic problems of instrument flight.
On this first flight, after a few turns, a stall, and slow flight have been
completed, you will put on blue goggles. These goggles in combination
with amber-glass windowshields will keep you from seeing outside while
enabling you to see the instrument panel inside the plane. You will
attempt to maintain straight and level flight. When you approach a
dangerous speed or attitude, you will be told to lift your goggles and
observe while the instructor recovers and returns the plane to a normal
flight attitude. If your reaction is normal, your attempts at flying in-
struments will be dramatically unsuccessful."
FLIGHT: APPROXIMATELY 30 MINUTES
The flight instructor should give the student as much information on
the plane as he can assimilate without detracting from the basic prob-
lem — that of giving the student a dramatic demonstration of his in-
ability to fly the plane "on instruments." It is important for the student
to feel that he can control the aircraft adequately, so that he will not be
able to use his lack of familiarity with it as an excuse for failing to fly
successfully in the simulated instrument setup.
The flight is divided into two parts. The first part is familiarization,
making the student feel at home in the aircraft. Give enough of a
cockpit checkout to acquaint him with the instruments. Identifying the
basic ones he has used in his previous flight training helps to accustom
him to the strangeness of a new aircraft. Let the student do as much
flying as possible without confusing him. Let the student actually push,
punch, and move the controls and switches. By doing most of the
thinking for him and using the "talk through" routine, there is little
that the student won't be able to do. As soon as practical after take-off
turn the controls over to the student and let him continue the climb out.
After leveling off, direct him to make a couple of 90-degrcc turns.
Follow this with slow flight, then a stall. Emphasize that these ma-
neuvers are made with the sole purpose in mind of familiarizing him
with the ain rafl and that there is no intention of grading his technique.
I i it. put him at ease; the more "at home" he feels with the instructor
and with th< air< rafl the more impressive his instrument experience will
be to him. Trying to impress the instructor, trying to learn too much
about the plane all at once, or other distracting factors will serve to
lessen the effect of his instrument attempt.
After the stall resume cruising flight, making sure that all the nec-
essary lights are turned on. Have the student put on the blue goggles
while you fly the plane. Let him become accustomed to the blue goggles
and the restricted light. Give him every "break" to make sure that he is
ready for his try at "instruments." You might say, "OK, you arc in the
overcast. Use any means you wish to keep the aircraft under control.
Try to hold a course flying straight and level. It's all yours."
The student should not be allowed to go beyond certain safety limits
in the effort to convince him he cannot fly instruments. These limits,
arbitrarily set, are:
( 1 ) Stall. An unintentional stall on instruments should convince any-
one of his inability to control the plane successfully.
(2) Airspeed of 185 m.p.h. If the instructor starts a recovery at 185
m.p.h., in all likelihood the speed will reach 200 m.p.h. Do not
exceed the redline limit of 202 m.p.h.
(3) Altitude of less than 500 feet. An impending crash with the
ground is an excellent "convincer."
(4) Prolonged loss of direction. It is helpful to draw the track of the
student's attempt to fly instruments. Because the student is
unaware of the gyrations being made, it is impressive for him to
see subsequently the aircraft track as drawn by the instructor.
The track should be drawn as near to scale as possible.
To accomplish the purpose of the first flight the instructor must let
the student go as far as safety permits. Usually, the student will end up
in a high-speed spiral dive. He will combine the factors of high-speed,
bank, dive, and proximity to the ground in a dramatic effect.
Normally, the lower the altitude at which the student makes his
instrument try, the more spectacular is his failure. However, the in-
structor must know the limitations of the aircraft. While he should not
exceed the bounds of safety before recovery, the closer the aircraft
comes to the limitations of altitude, airspeed, etc., the more impressive
is the result to the student.
If the student loses control of the plane in a very short time, say 30
seconds, it is advisable to offer him another try. Sometimes a student
will lose control so quickly that he may not realize the seriousness of the
problem. He may rationalize, "I didn't have a chance to get settled."
Three tries are generally the maximum before going on to the rest of
the course. The student first must be convinced that he cannot fly
After completion of the simulated instrument part of the flight the
instructor will take over and fly back to the field. On the return trip,
discuss the student's efforts and answer his questions. The student may-
need to relax as the experience of the "unknown" takes a lot of nervous
energy. More will be accomplished by discussion on the ground where
he will be ready to consider the problem seriously.
POSTFLIGHT DISCUSSION: APPROXIMATELY 20 MINUTES
"Now let's take a few minutes to talk over the flight and see what
happened. Let's examine the problem of the tremendous load one can
impose on a plane in a graveyard spiral maneuver. Occasionally you
read in the paper that a farmer saw a plane come diving out of the
overcast, right itself momentarily, and then he saw a wing 'fall off.'
Wings do not 'fall off' airplanes. They can be 'torn off' but they do
not 'fall off.' Without being too technical, I would like to go over some
of the structural limitations and the load factor considerations which
every pilot should know about his airplane.
"As you and I are sitting here there is a load of one G on us. That
is, I have one times 168 pounds acting on me right now. You have one
G or one times 170 pounds acting on you. In straight and level flight
we have one G or one times the force of gravity acting on us. Every
pilot should realize that the load on an airplane increases as the angle
of bank is increased in a turn. This extra load is due to centrifugal
force. But how much does this centrifugal force add to the load of our
plane when it is banked? Let's examine a table.
Degree of Bank Load ( G ) on Wings
(Level Flight) 1 G
50 1.56 G
60 2 G
70 2.92 G
80 5.75 G
"The above table holds true for a coordinated banked turn while
holding a constant altitude Note how the effective load on the wings
increases with the change of bank. For example, in a 60 degree bank
our Bonanza, instead of weighing 2700 pounds, weighs 5400 pounds.
This banked condition is only a part of the uncontrolled downward
spiral you were in.
"Try to picture now what you would have done had you actually
popped out of an overcast headed right at the ground. The instinctive
reaction is to pull back on the stick — and if you are only a few hundred
feet above the ground when you come out of the clouds you don't have
much choice, do you? You've got to make a quick pullout or you'll hit
the ground. Let's look over a simple formula covering this exact situa-
tion which assumes a 90-degree curve could be flown instantaneously.
LOAD IN ABRUPT PULL UP = ' '
"Take your first attempt at flying instruments as an example. Your
entry speed, or the speed you had when you broke out of the overcast
(when you lifted the blue goggles), was 200 m.p.h. The normal stalling
speed of the Bonanza with the wheels and flaps up is 65 m.p.h. A little
figuring shows that to make an abrupt pull up under those circum-
stances would have loaded the plane with approximately nine Gs. That's
enough to tear an airplane apart. The Bonanza has a limit load factor
of 4.4 Gs. That is, the Bonanza, according to the Handbook, is perfectly
safe under a load of 4.4 Gs. It has an ultimate load factor of 6.6 Gs;
at this point the plane has a perfect right to come apart. Your reaction
can very well be, 'Why don't they build them stronger?' The fact is
that the Bonanza has a higher load limit than most commercial air-
liners in operation today. The Civil Air Regulations allow transport
category airplanes (DC-3, Constellation, etc.) to have a maneuvering
load factor as low as 2.5 Gs. Considering the added load during a bank,
plus the load imposed in an abrupt pull up, it isn't difficult to see that
a pilot can tear a plane apart. This condition can and often does exist
for noninstrument pilots emerging from an overcast in a high speed
"The whole purpose of this first flight was to show you that you
cannot control the plane unless you have some outside visual reference.
You are not an instrument-rated pilot. Don't get the idea that instru-
ment flying is for supermen. That's not the point at all. Ability to fly on
instruments is simply a skill acquired through training and practice.
But without that skill it can be fatal to try to fly 'on instruments' —
as you saw from your attempts. Ideally, every pilot should continue his
training to become a qualified instrument pilot. This not only is the
best life insurance he can get, but it also enables him to utilize his
aircraft more effectively. However, we know that not every pilot has
the time or the money to spend in getting an instrument rating. Yet,
sooner or later, if a pilot flies long enough, he is likely to encounter
weather that he was not expecting and will find himself 'on the gauges.'
It is for this situation that we have devised an emergency self-saving
system, a procedure to 'get out of the bad weather and back to where
you can see the ground."
Purpose: To introduce the emergency self-saving procedure.
PREFLIGHT DISCUSSION: APPROXIMATELY 15 MINUTES
"In the first period, we saw the problem of instrument flight. Just the
realization that a problem exists puts us ahead of many pilots who think
that if they ever should get on instruments, somehow or other they
would be able to get through all right. We know from our first flight
experience that this is not so. A person without instrument knowledge
and experience simply cannot fly the plane once he has lost all outside
references. For this reason we are proposing an emergency procedure
that a 'contact' pilot could use should he get caught in a storm or
overcast. We don't say this is the only solution to the problem, or even
that it is the best solution. However, it is a solution and one that, if
followed properly, will work. It could save your life.
"Your first thought on encountering instrument flight conditions
should be to get positive control of your plane. With that end in sight
let's first examine the steps of the emergency self-saving procedure. The
steps will be placarded in a prominent place on the instrument panel.
Your job when you lose visual reference outside the plane will be to
read and do the five steps.
"The placard in our Bonanza reads:
1. Hands off Center Needle
2. Gear down Center Needle
3. Throttle back Center Needle
4. Trim to mark Center Needle
5. Throttle 17" r.p.m. high Center Needle
"(1) Hands off. This step is essential to the technique. The nonin-
strument pilot is as likely to make the wrong control movement
as the right one when he encounters instrument flight conditions.
By taking his hands off the stick or control wheel he will avoid
'man handling' the plane into any unusual attitudes. The hands
off technique will allow the plane to make use of its inherent
stability and will allow it to seek out a predetermined airspeed.
After you have done this a few times without the goggles and
have seen the result, you will build up confidence in the plane's
doing the right thing, and later on in the course you won't want
anything to do with the control wheel. You'll know that the in-
herent stability of the plane will do a better job than you can do.
"If you were capable of using the wheel under instrument
flight conditions and could interpret the instruments well enough
to know what to do, then you would have no need of 180-degree
instruction in the first place. But since you are not an instru-
ment-rated pilot and cannot, without training and practice,
interpret the instrument readings properly then it is best to rely
on the stability of the aircraft to avoid maneuvering the craft
into radical positions from the false information of your senses.
"(2) Gear down. Lowering the landing gear helps slow the plane
down. One of the problems we have to solve is the transition
from cruising speed to a positive control slower speed. Lowering
the landing gear is a positive and easy way of reducing the speed.
"(3) Throttle back. The system still 'works' whether the throttle is
closed all the way or not touched at all, but the system improves
when the throttle is reduced to partial power — power just
"(4) Trim to mark. The trim tab is moved to a predetermined mark.
That mark is the trim setting which will give us 95 m.p.h. in
the Bonanza. Our goal is to get the approximate approach
speed of the aircraft. This is a speed that is well below the high
speed of the 'graveyard spiral,' slow enough so that it is difficult
to build up much of a G load, yet a speed that gives us positive
"(5) Throttle 17 inches, r.p.m. high. You can see the desirability of
setting the throttle to a position that will enable us to hold alti-
tude, neither gaining nor losing. That is exactly what we have
done. A mark put on the manifold pressure gauge gives the
power setting that will hold a constant altitude. It is marked by
a piece of tape and happens, in this ease, to be 17 inches of
Ln fold pressure. This must be predetermined for every an-
72 It I desirable to have the propeller in the full low pitch
o7 high r.p.m. position. In effect this gives us a fixed-pitch
poSer. Any intermediate propeller pitch position would be
too difficult to arrive at accurately due to the constant vanatron
of the rp.m.'s as the plane goes through its tmtial osculations.
"In the interest of clarity the continuous step of centering the needle
is discuss d last In practice it most certainly does not come last nor
L t om only at the first part. Attempting to keep the a.rplane
! • L Id level' bv keeping the turn indicator averaging out in the
cenSt o P — importance, and it must be a continuous opera-
t or It is this instrument which indicates whether the airplane is turn-
tion. It is this "* um tum indicator or needle is controlled with the
ing orgoing straight The turn i ^ ^ ^ ^ . (
SSLST^-tf burning to the left. Right ruddr pressure
will roll the airplane back to straight and level flight. Ihe needle wii
2: v s indtateany turn the airplane makes. We have no interest m the
ball part of the instrument and from here on will ignore it.
AIRSPEED AND AITITUDE
AIRSPEED AND ALTITUDE
"It is vital that you understand that the airspeed is controlled by the
trim s ting and that the altitude is controlled by the power setting
Ss rvTew some basic concepts with a hypothetical flight in an
inc Champion. In the air, suppose that you control the throttle
and I control the stick. Flying in this manner, I chaflenge you o do
anything in your power to keep me from holding 65 m.p.h Your nrst
Stion may be to put on full throttle. Obviously all that is necessary
me to hold 65 m.p.h. is to give a little back pressure on *g*
and enter a climb at 65. What about reducing the power . * . In
this case, I let the nose drop and we keep an airspeed of 65 "i-P-h- m>
glide. The moral, of course, is that the airspeed - -ntrolled b> the
stick. For our purposes wc can substitute the trim tab fot : the ^ tick.
",„ th e same vein, I might say to you, OK same rules 1 ake Ae
„„,„„,, v „„ take A,- stick. Now let's sec you hold your atoude. When
, M , the power at idling is then- anything you can do to A contxo
stic k to keep the airplane from descending? Absolutely not. The throttle
"This technique was devised to make it as universally applicable as
possible. Civil Air Regulations say that every airplane must have an air-
speed indicator, an altimeter, a magnetic compass, and certain power in-
struments. For such an extremely limited instrument experience as we
are proposing, some kind of attitude instrument is necessary. The turn
indicator is used here since it is extremely reliable and comparatively
inexpensive. Presumably other instruments might be added, but for our
purpose we shall use only the above."
MECHANICS PLUS TECHNIQUE
"Think of the technique as being divided into two parts: (1) The
process of getting the airplane under control is purely mechanical. You
read the placard and do what it says. Certain switches and controls
must be punched or pulled. No particular skill is involved. Anyone who
can read can do the mechanical part of the procedure. (2) The tech-
nique involved in the procedure comes in learning to interpret the turn
indicator and the magnetic compass. The majority of our time will be
spent in learning to visualize what those two instruments are telling us
and in learning how to control them.
"In the mechanical procedure you actually eliminate several instru-
ments that you normally have to watch. By setting the trim we eliminate
airspeed consideration since we know that the plane is going to seek
out 95 m.p.h. Setting the power lets us forget about the altimeter until
time to descend. In effect we have eliminated everything but the turn
indicator and you can give this instrument your full attention. An
occasional glance at the magnetic compass will give the directional
information you need."
"In the transition from cruising flight to slow flight you very likely
will experience pitching oscillations. How severe these oscillations are
will depend on how smoothly you do the outlined steps, i.e., the me-
chanical part of the procedure. The oscillations in themselves are not
dangerous. As long as you complete the five steps within a reasonable
length of time, and as long as you exercise a moderate amount of control
over the turn indicator, the airplane will not reach an excessive speed —
in fact, the highest speed is almost sure to be the speed at which you
started — nor will the aircraft stall. The oscillations may make it more
difficult to control the turn indicator with the rudders, but they are not
"TetTbriefly touch on the use of the rudder to control our turns and
. V^ and level flight When you learned to fly you were taught that
bvThangTng the At tree actin on an airplane you could bank it and
• T " t ,,rn the Diane You learned that to make an airplane bank
ou lytHng new? Is this a radical departure from what you learned?
D elded y not. What happens when you apply rudder pressure? Lets
fay tha you exert pressure on the right rudder. The rudder control
Z yawing motion about the vertical axis so when you push nght
udder tne nose of the aircraft goes to the right. As the nose moves so
7 he wines since they are attached to the same plane. But in the
Tarn moun of Tml th/left wing must go farther than the right wmg
since H going around the outside of the circle. This means that the
ftwng is going faster than the right wing. Increasing speed ts one way
of increasing lift, so in this case the left wing — ntarfly gets ™
lift and the airplane goes into a bank. Now part of the total hft force
is acting to the side and gives the force necessary to turn.
"This is nothing new; the same principles you learned when you
started flying still hold true. Bear in mind that this whole procedure is
a Vmmick' designed to save your life. If it is easier and safer for us to
makeT' loppy' turn in orde/to get the job done, then that is the best
way under the" circumstances. All turns will be shallow ones and expert-
ence has shown that the altitude lost will be negligible.
PREFUGHT DISCUSSION CONTINUED IN THE AIRPLANE
"Let's take a minute here in the airplane to go over the procedure
and be sure that we have it in mind. We will go over it several times
Wore we start the engine and again while we're checkmg the plane a
th£ en d of the runway, and then several more times m the air before
V( „, put on the goggles. By then you will find that you are familiar with
L steps and won't have any difficulty in doing them. He re is the
l a( ;,„, n the instrument panel; let's take the steps individually.
"Needless to say you will be making a constant effort as you go
„,„;,„_,,, „„. proced ure to center the turn indicator. Without this vita,
tinuous step the system is useless. This does not mean that you
,1,1 hesitate or pause between steps to get the needle perfectly in the
, ente. Rather il means that as you are going through the system, if you
,, tha( the needle is off to one side, indicating that you are in a turn
ih that direction, you should apply opposite rudder pressure to start the
,,„, ,,,, | to a level attitude as you continue with the steps. After you
have completed the steps then you can concentrate your attention ex-
clusively on the turn indicator.
"(1) Hands Off. Take your hands off and leave them off. You have
no further need of the control stick. It doesn't hurt to be a bit
dramatic about it. Let go of the wheel as though you really
"(2) Gear Down. Reach over and put the landing gear switch in the
down position. Once you've done that go right on to the next
step. There is no need to watch the gear position indicators.
"(3) Throttle Back. How far back? Ideally you should throttle back to
partial power, slightly above idling. A manifold pressure of
somewhere between 10 and 15 inches is fine. However, do not
watch the manifold pressure gauge. Without hesitation move the
throttle back several inches to what you consider the right posi-
tion. It will take only a few times before you will be able to put
it right where you want it without taking time to check on the
MP gauge. Actually it isn't vital to the procedure to set the
throttle accurately, but it makes the system much smoother;
this in turn makes it easier for you to control the turn indicator.
It is important to go immediately to the next step of putting the
trim tab to the mark, since the steps of putting the gear down
and the throttle back will give the nose of the plane a down-
ward pitching movement.
"(4) Moving the Trim. Moving the trim to the mark will partially
offset the gear down and throttle back steps, and, if done prop-
erly, will help in a smooth transition from cruise to slow flight.
As was explained the trim tab is predetermined and in the Bo-
nanza is set to give a speed of 95 m.p.h. Put the top edge of the
green sector of the trim tab indicator at the top of the trim tab
indicator window. This is an easy way to get the desired setting.
Move the trim tab wheel slowly toward nose up until you see
the division between the green and white sectors on the trim tab
indicator. Then move the top of the green to the top of the
window. Move the trim tab wheel slowly. Moving it too quickly
is the same as abruptly pulling back on the wheel. Moving the tab
too quickly is not dangerous, but there will be steeper oscillations
and it will be more difficult to control the turn indicator.
"(5) Throttle to mark, r.p.m. high. There is a reason for taking step 5
in this order. If the throttle is set at only slightly over idling,
and you try to change the pitch of the propeller to high r.p.m.
(low pitch), you will find that it may take as long as 30 seconds
or more. The best technique is to advance to 19 or 20 inches
of manifold pressure. Then, when you change the pitch of the
propeller to get high r.p.m.'s, you will find that the manifold
pressure will drop and you will have approximately the correct
power setting, namely 17 inches. It may be necessary after
changing the propeller pitch to make a slight adjustment of the
manifold pressure. Line up the MP needle with the tape indi-
cator on the face of the MP gauge and you will have the right
setting for holding a constant altitude."
"You will find it helpful to read the steps aloud as you go through
them. Actually talk yourself through the proper procedure. Talking to
yourself makes you conscious of what you are doing. Anything you can
do to make yourself deliberate and positive will give you more
"Go through the procedure now, actually touching the landing gear
switch; move the throttle and trim tab; go through the steps several
times; get yourself thoroughly familiar with the various controls.
"Now let's pretend that you are on the way to Chicago. We're flying
along contact; you have your hand on the wheel and your feet on the
rudder pedals. Somewhere in the vicinity of Kankakee we start to get
into weather that doesn't look good, but we have important business in
Chicago so we are determined to get there. That's our first mistake,
of course. It is folly to 'push' the weather. Look out your side of the
cockpit. You can't see the ground. Look over through my window;
nothing but milky white clouds. We're in trouble. We're 'on instru-
ments.' Now is the time for our emergency self-saving system. OK, fire
away." (Student, still on the ground, goes through the mechanical
"Bear in mind that you should do the steps as quickly as you can
comfortably do them. It is a purely mechanical process. Read the
pla< ard and do what it says. Think of the procedure as a 440-yard run.
It isn't a 100-yard dash; that is, it isn't necessary to hurry or get ex-
< ited. Yet it isn't a two-mile run either. Go about the steps in a busi-
ness-like fashion and get the job done. Do them quickly; pace as you
would in a 440. Let me emphasize again that as long as you do the
steps you'll not lose control of the aircraft. But, if you take too long to
do them, or do them in an erratic or hesitant fashion, you will lose
altitude or set up severe oscillations. It's not difficult to get the job done
properly. Read the placard; do what it says; and then you are free to
concentrate on the turn indicator."
As a general rule, let the student do the flying. Make him think for
himself as much as possible. However, when he appears to be tiring, it
is good procedure to take over for a minute. Let the student make the
take-off. Climb-out is made to an altitude of approximately 2000 feet
above the ground. At this point the instructor should take the controls
and make a visual demonstration of the procedure to the student. The
purpose is to prepare the student for what to expect and to provide
him a model on which to pattern his attempts. The instructor should
make an effort to complete the procedure as smoothly as possible, re-
peating the steps aloud as he does them. After the steps have been
completed the instructor should allow the plane to go through the
oscillations. He should call the attention of the student to the fact that
the plane does settle down to a constant altitude and that the airplane
does seek out the predetermined 95 m.p.h.
Don't hurry this first demonstration. The student should have every
opportunity to verify what he has been told by watching and feeling
the actions of the airplane. Point out to the student that there is no
danger or difficulty in taking the hands off the wheel; the plane can
easily be controlled by use of the rudders.
Questions should be encouraged. The initial demonstration will
normally require 5 minutes. If the air is rough, it is best to continue the
climb until the air is smoother. The first demonstration should be as
clear as possible, thereby convincing the student that the inherent
stability of the aircraft will take care of the oscillations. If the procedure
is accomplished properly, the transition from cruise to slow flight can
be made with very little oscillation.
The instructor should return the plane to normal cruising flight and
turn it over to the student, who now will visually attempt the self-
saving system. At first the student may be apprehensive. If he is hesi-
tant, the instructor should talk him through. Pointing to the placard
and reading aloud the steps may help him to get started. On the stu-
dent's first visual try, he should be allowed to take enough time to
convince himself completely of the plausibility of the system. Let him
control the attitude with the rudders and if there are any oscillations be
sure that he "rides" them out in order to prove to him that the plane
will eventually seek out the predetermined airspeed and will then hold
a constant altitude.
The student should repeat the procedure three or four times without
the goggles. After the first time, if he is convinced that the aircraft will
react the way he has been briefed, it is not necessary to carry each
practice attempt to its ultimate conclusion. If the instructor believes that
more knowledge will follow by interrupting the student at the time of
error, he should do so; e.g., if the student rolls the trim tab the wrong
way it may be best to start over again. Allowing the student to complete
the procedure and then pointing out errors is a most effective method.
After the instructor has demonstrated the system once, and the stu-
dent has practiced it three to five times visually, the student should
have the system well enough in mind to try it under the simulated in-
strument condition. The transition is more easily made if, after the last
time through the visual trials, the student puts on the goggles and prac-
tices controlling the plane with the rudders. Now, for the first time, he
will have no outside cues as to the plane's attitude and will have to
rely solely on the turn indicator. It will take him some time to get used
to the idea and to the limited light available through the blue goggles.
Let the student practice flying the plane straight and level; then
permit him to make gentle turns. Remember that the turns are to be
made at %-needle width, with a maximum of one needle width. Stress
that the turns should be made with a shallow bank. As the student
improves in his efforts to control the needle it is helpful in teaching
and will build confidence if the instructor will occasionally let the stu-
dent lift his goggles and observe the attitude of the aircraft. In other
words, if the turn indicator indicates that the plane is in a turn, let the
student see what is happening. If he thinks the plane is straight and
level when in reality it is in a turn, nothing is so convincing as lifting
the goggles and observing the attitude.
After a few minutes of controlling the plane under the goggles, the
student should lift the goggles and either he or the instructor return
the plane to a normal cruise. Now the student attempts the whole
operation. The instructor should strive from the beginning to make the
problem of "accidental instrument flight" as realistic as possible. In the
cruising attitude the student puts on the goggles, then (1) gets the
aircrafl under control and (2) with the instructor acting as the com-
makes a turn to the reciprocal of his original course, and (3) with
information given him by the instructor begins a normal let-down.
Again, in the normal let-down it is important to call to the student's
attention that although he is gradually losing altitude, the airspeed
remains approximately 95 m.p.h. Also, he should be given a "look"
from under the goggles to see his deseending attitude in relation to
CONTROLLING THE TURN INDICATOR
The technique of controlling the turn indicator must be taught al-
most wholly in the air.
(1) "Averaging" the turn indicator. It is important that the student
understand that proper control of the turn indicator is largely
a matter of correct interpretation. In order to control the turn
indicator correctly it is necessary to average out its readings.
It is not an easy instrument to read. The needle fluctuates from
side to side, especially in rough air, and the problem is to read
it in terms of an "average." The student must understand that
in order to maintain straight and level flight, he must make the
needle travel the same amount on each side of the center mark.
It doesn't make too much difference how much the needle is off
center. Rather it is a problem of how long it is off center. Even
Vs of a needle width if not corrected will, in a matter of minutes,
give a 180-degree, even a 360-degree, turn. At some time during
the course the instructor should demonstrate, with alternating
rudder pressures, how the needle can swing from side to side,
hitting the stop on each side, with the airplane actually still in
a straight and level flight attitude. In straight and level flight
the object is to control the rudders so that the needle averages
straight up. The same is true for a turn, only now, instead of
averaging the needle in the straight up position, it is averaged
3 A of a needle width on the side of intended turn.
(2) Parallax. Parallax is the apparent displacement of an object as
seen from two different points. Depending on the position of the
turn indicator in the plane, parallax may well be a factor with
which to contend. In this study the turn indicator in the Bon-
anza was just to the right of the center line on the instrument
panel. Since the student was seated in the left-hand side it was
difficult to read the turn indicator. If the student "centered" the
needle without considering parallax, he would actually have the
needle slightly to the left of center giving the plane a slight turn
to the left. The student must mentally project himself directly
in front of the needle to control it properly. If a student always
errs to the left during practice, in all likelihood he is not making
sufficient correction for parallax.
(3) Torque. Another consideration in the technique of controlling the
turn indicator is torque. The designer rigged the plane so that
it could be flown without right or left rudder pressure at cruis-
ing speed. In the self-saving system the airplane is trimmed to
seek out the approximate approach speed. In situations where
the air speed is comparatively low and the power is compara-
tively high (such as in take-off* or climb), the torque effect is
noticeable. Normally this is taken care of by additional right
rudder pressure. So, in the process of controlling the plane with
the rudders it is quite possible that the student will maintain
some right rudder pressure to keep the needle averaging out in
the center. This is normal since the speed is well below cruising,
with almost cruising torque effect.
Purpose: (1) To explain and demonstrate the peculiarities of the mag-
netic compass so that the student will understand and be able to use it
as his sole direction-indicating instrument. (2) To put together the
information the student has learned to date, so that he thinks and acts
on the problem as a whole.
PREFLIGHT DISCUSSION: APPROXIMATELY 25 MINUTES
"Let's briefly review our problem: We are on a cross-country flight.
In spite of our best efforts we find ourselves in instrument flight condi-
tions. The first thing we'll do is to get the aircraft under control by
going through the steps. But maintaining control of the plane isn't
enough. We have to find our way back to good weather. The problem
boils down to four considerations:
I I Control. This involves the process of getting the plane under
control by doing the self-saving steps.
(2) Direction. After the steps have been completed there is no guar-
antee that the plane is still on the original heading. This will
depend on how well the pilot has done the steps. However, the
original heading is not of particular importance as long as we
< an find out what heading we are now on. The second direction
we are interested in is the reciprocal heading to our original
course. Presumably we could see the ground where we came
from and it is our desire to get baek there. So the two directions
we want to know are:
(a) What direetion are we going now?
(b) What direetion do we want to go?
(3) Turn. We know whieh way we're going now. We know whieh way
we want to go. Now the problem is to turn to the desired
(4) Let-down. If after a reasonable time we don't break out of the
instrument flight conditions by flying back towards the good
weather we may need to consider a let-down.
"That's the problem as a whole. Now let's specifically examine the
instrument that will give us the direction information vital to our
"We shall consider only the panel-type magnetic compass. That is
the kind in this aircraft and the one most commonly used. There is a lot
of similarity between the turn indicator and the magnetic compass in
that both instruments need interpretation in order to read them cor-
rectly. After the aircraft is under control, your next thought will be to
find your heading. You must bear in mind one important rule: NEVER
JUMP TO A CONCLUSION. Don't rely on only one reading of the
magnetic compass. You can't look at the instrument only once and get
the information you want.
"Concentrate on the turn indicator and fly the airplane straight and
level, holding it as steady as you can. Once you feel you have the plane
under fairly good control and think you are straight and level, then
look up at the magnetic compass and make a mental note of the com-
pass reading. Immediately return your attention to the needle and
continue your efforts at holding the plane steady on a straight and level
course. After some twenty seconds take another reading on the compass,
make a mental note, and again return immediately to the turn indicator.
In smooth air a minimum of three readings should be taken to ascertain
an 'average' correct reading of the magnetic compass. In rough air
you must continue to take 'readings' on the magnetic compass until
such time as you have definitely determined your plane heading.
"At this point let's make a distinction. Do not think of turning until
you have made a positive identification of your general direction within,
say, 30 degrees. It is not particularly important to determine to the
exact degree your heading. The time to strive for accuracy is when you
have turned onto the reciprocal course. Now you are interested only in
positively determining your general heading.
"Now you know what direction you are going. Next you must figure
out what direction you want to go. This should not be too difficult.
You are on a cross-country flight; you know the course that took you
into the bad weather. A simple mental arithmetic problem will give you
the reciprocal course that will take you back to VFR weather. The
problem has now become one of turning to your reciprocal course. If
on completing the steps you find that you are within fifteen to twenty
degrees of your original course, which direction to turn is not important.
However, if it is definitely closer to turn a certain way, say to the right,
to get to the reciprocal heading, then turn in that direction. Always
turn the short way around; this will avoid possible confusion, and will
get the job done more quickly. Now let's consider how to use the
compass in making our turn."
"In turning to a heading of either East or West the compass will
give you a reliable indication of your actual heading, i.e., if you roll
out of your turn when you see East on the magnetic compass you will
actually end up fairly close to a heading of East. In making a turn to
a heading of West if you roll out when you see West under the lubber
line of the magnetic compass, you'll find your heading is West. In other
words, when you are turning to a heading of East or West you can
assume that your magnetic compass is giving you reliable information,
and you can roll out as indicated.
"This is not true when turning to a heading of North. In order to
end up on a heading of North you must roll out on a magnetic compass
reading 30 degrees prior to North, i.e., you must 'lead' North by 30
degrees. When making a right turn to North, roll out when the magnetic
compass reads 330 degrees; when making a left turn to North, roll out
when the magnetic compass reads 30 degrees. Once you have started
'.in roll out, concentrate exclusively on the turn indicator to complete
the turn and to hold a straight and level course. After the compass
swings back and forth a few times it will settle down on North.
"Turning to a South heading is yet another story. In this ease you
must go past or 'lag' South 30 degrees on the magnetic compass in order
to end up on a heading of South. Example: On completion of the steps
'mi determine your heading to be 315 degrees, or generally NW. You
know thai tin- 'good weather' is to the South, and it is your intention
to turn to a South heading. What will be your reasoning in this situa-
tion? To turn from 315 degrees to 180 degrees the quickest way will
involve a turn to the left. Our rule says to go past the South reading of
the magnetic compass by 30 degrees. In this case we shall have to roll
out of the turn when the compass reads 150 degrees. Again, once you
see the 150-degree reading on the compass, roll out and concentrate on
the turn indicator. Fly straight and level for at least a minute while the
compass settles down. Now do the same thing that you did originally
to find your heading, mentally averaging out the readings of the mag-
"We have considered the cardinal headings. What about the headings
in between? Assuming a course of 045 degrees took us into instrument
flight conditions, to get out we would want to fly a reciprocal course of
225 degrees, or Southwest. We know that to turn to West we roll out
when we see West on the magnetic compass. To turn to South we know
that we have to go past, or lag, the South reading of the compass by 30
degrees. Logically then we might expect that for half way in between
the two we would split the difference, and that is exactly what is done.
In the above case if we were turning around to the left we would go
15 degrees past the 225-degree compass reading before starting the roll
out; we would roll out when the compass reads 210 degrees. If we had
gone around to the right from 045 we would have had to roll out when
the compass read 240 degrees." (Ground training is most important here.
Give the student problems on figuring out his reciprocal headings and
the compass readings that he should see in order to roll out on these
headings. Cover the cardinal headings plus NE, SE, SW, and NW. He
should know these calculations before going into the air.)
PROPER DEGREE OF BANK
"Any bank in excess of one needle width will usually give erratic read-
ings on the compass. If the desired bank of M-needle width is used, then
the compass will give the expected reaction. 19 If there is any error it is
much better to err on the shallow side. Too steep a bank can give
erroneous readings as great as 180 degrees from the actual heading of the
aircraft. Avoid anything over a one-needle width turn."
MAKING SMALL CORRECTIONS OF DIRECTION
"After you have completed your turn back to 'good weather' you
again must go through the process of taking readings on the magnetic
19 If the instrument is calibrated for two needle widths as a standard rate turn,
a one and one-half needle width turn should be used.
compass. Let's assume that you have determined that your present course
is 20 degrees off the course you want. However, you should strive to
get as close to the 'right' heading as possible. Two methods to do this
are suggested. Either one or a combination of the two can be used.
"(1) 'Sneak' method. The 'sneak' method involves using a very shal-
low turn to creep or edge back to the heading wanted. By doing
this we are able to avoid most of the compass errors and can
use the compass as a direct direction-indicating instrument. This
method is especially effective in arriving at an easterly or west-
erly heading since there is little compass error involved in turn-
ing to these headings. The danger involved in this method is
that you may not be 'sneaking' as well as you think. Perhaps you
are actually making a medium-banked turn. In this case you
might easily turn farther than you intended. Mental stress and
unfamiliarity with compass peculiarities could well lead you into
a large error. This type of error can be avoided by using the
"(2) 'Timed-turn method. A standard rate turn in a light single-
engine aircraft is considered to be a turn made at the rate of
3 degrees per second. For example, a standard rate of 3 degrees
per second would mean that a 180-degree turn would take one
minute; a full circle or 360 degrees would take two minutes. Now
let's again consider the 20-degree correction we have to make
to get exactly to our heading. Twenty degrees divided by 3 de-
grees per second gives us a quotient of 6 to 7 seconds; that is,
if we make a 6- to 7-second %-needle width turn we will have
turned approximately 20 degrees. With this method you will
never make the large errors which can easily be made when
using the compass. Turns are made with the turn indicator.
Count the required number of seconds for the degree turn de-
sired, roll out, hold the turn indicator as nearly centered as pos-
sible, let the compass settle down, and again go through the
process of taking several readings on the magnetic compass to
determine if you did get the amount of turn you wanted. This
method may seem cumbersome at first but a little practice will
show you that timed turns can be made easily. In turning to
northerly or southerly headings particularly you may find timed
tin us less confusing than using the compass to make a small
< oi M-c tion."
"Two dont's which are really the same thing said two different ways
"(1) Don't jump to a conclusion. Always take several readings on the
magnetic compass before you act on the direction indicated.
Remember, unless you are holding the airplane straight and
level, the compass is likely to give you an assortment of erratic-
"(2) Dont chase the compass. The turn indicator is the instrument
that gives you attitude information. It will tell you when you
are straight and level; it will tell you when you are turning.
Approximately 85 per cent of your time and attention will be
spent watching and reacting to information given you by the
turn indicator. You will want to keep a constant check on your
direction progress, but this can only be accomplished by never
believing just one reading of the compass. Always read it over
a period of a minute (longer in rough air) to insure that your
initial reading was not taken at the extreme swing of a compass
oscillation. Chasing the compass, turning immediately with every
reading on the compass, can lead only to confusion. The com-
pass gives you a check on how well you are holding your direc-
tion with the turn indicator, but be sure you have them in their
proper perspective. The turn indicator is the instrument that
enables you to control the attitude of the plane while on in-
struments. It is all important. The compass is a direction-finding
instrument, and that's all it is. Used in the manner you've been
told, it is an extremely reliable and important instrument. Don't
try to get its information too quickly. When you have decided
definitely what direction it is indicating, act on it; don't chase
LEAD OR LAG
"The number of degrees of lead or lag will roughly equal the latitude
of the particular area in which you are flying. The exact number of de-
grees must be determined experimentally. Generally, in the midwestern
egion, you will find that 30 degrees is the correct amount."
FLIGHT: APPROXIMATELY 35 MINUTES
The student on entering the airplane will again briefly review the steps
Df the procedure. At this stage he should be doing almost all of the flying
and actual manipulation of the plane. He will start, taxi, take off, and
climb the plane to approximately 2000 feet. Here the instructor will take
over and make a visual demonstration of the behavior of the magnetic
compass. Starting on a heading of East and working around the compass,
he makes a convincing demonstration. The instructor should ask the
student on what reading of the compass he should start his roll out as he
approaches North. Point out to the student that by rolling out on 030
degrees the plane actually ends up on a heading of North. Try to make
the turns as smoothly as possible so that the demonstration will be most
convincing. Complete the turn when the compass indicates it should be
done. If the heading is somewhat off course tell the student why and indi-
cate how he would make his correction. From North continue around the
compass rolling out on West, South, and finally East. At each point let
the student indicate on what compass reading to roll out, bringing his at-
tention to the actual heading of the aircraft at the completion of each
While on a heading of East the stage is set for a very convincing
demonstration of some of the peculiarities of the magnetic compass.
Declare, while on the heading of East, that it is your intention to turn
to a heading of North, assuming that, like the too-large majority of
private pilots, you are not familiar with the behavior of the magnetic
compass. You reason that since you're on a heading of East you must
make a left turn to get to North. The turn is started and the compass
begins its rotation. You note that the plane is making progress towards
North, but very slowly; you steepen up the turn somewhere in the vicinity
of 50 degrees on the magnetic compass. The compass now actually slows
down and appears to move hardly at all, so you increase the rate of turn
slightly in order to "get around to North." By this time the turn is
over a standard rate turn. The compass will "stick" somewhere between
b() and 'M) degrees until the actual heading of the plane approaches West.
As you approach West, gradually shallow out the bank and call the
student's attention to the fact that the compass swings erratically and
thai HE NEVER SAW NORTH ON THE COMPASS. (We are using
the panel-type magnetic compass.) Continue around the turn and, if
in < essary, make another demonstration of this startling phenomenon.
Anothei fact with which to impress the student is that the compass mo-
mentarily reads exactly 180 degrees opposite his actual heading. Use this
demonstration to re-emphasize some conclusions : (1) Don't jump to con-
i lusions with Ui< magnetic compass. Take enough time and several read-
ol tin compass to determine positively what direction it is telling
you. (2) Avoid any bank that is in excess of a standard rate turn.
(3) Attempt to maintain a constant rate of turn. Varying the bank will
make the compass oscillate, making any precision in using the compass
At the conclusion of the magnetic compass demonstration the student
has all the necessary information to do the complete procedure success-
fully. He needs now to put all his information together and practice. In
the future, emphasize the problem as a whole. Dramatize and make the
simulated problems as realistic as possible. The student may need more
practice in doing the steps necessary to get control of the aircraft. If so,
be sure he masters them before continuing. He is then ready to do the
"whole" routine. Something along these lines is suggested.
"Let's assume we're on a cross-country flight to East St. Louis. We're
cruising along at 2000 feet. The weather doesn't look too good, but we
feel sure that we can make it there before the front moves into the area.
Our course is 225 degrees. We're just starting to let down a bit in order
to get underneath the clouds when, WHAMBO, we're in it. OK, you've
got it." (As the instructor says this, the student should have the goggles
on to get used to the restricted light in the cockpit as seen through the
Now the student has the entire problem of control, direction, turn, and
let-down. At first he may need some assistance, such as reminders to
watch the turn indicator, shallow out the bank, etc. As the student
progresses, every attempt should be made to make him as self-sufficient
as possible. After he has gained some proficiency the only information
that he ought to need from the instructor is (1) the problem: where
he is going, the circumstances of the flight, and the fact that he just ran
into instrument-flight conditions, (2) any weather information needed to
indicate a possible let-down, and (3) the end of the problem.
To inform the student of his progress and make the instruction easier,
show the student where he is starting the problem, i.e., give him his
geographical location and let him see it before he starts the problem.
When he has completed the turn and made his way approximately five
miles back beyond his starting point, it is logical to assume that he has
returned to the "good" weather. When he is told to lift his goggles call
his attention to the relation between his present position and his starting
It is not necessary to incorporate a let-down into every practice run
through the steps. However, it is practical to have the student make
a let-down on the practice run immediately prior to the return to the
airport. The instructions should have enough variety so that the student
is thinking for himself but still performing the steps as routinely and
mechanically as possible.
Time will probably not allow more than two or three practiee trials
of the system during period 3.
Periods 4 and 5
Purpose: To attain proficiency in the procedure. Since the mechanics
of the system should take little time to perfect, the majority of time will
be spent practicing the technique of controlling the turn indicator with
the rudders, along with practicing the proper use of the magnetic compass.
PREFLIGHT DISCUSSION: APPROXIMATELY 5 MINUTES
At the end of period number 3 the student has all the necessary infor- l
mation to do the procedure successfully. From here on it is constant
practice. The discussion will take the form of review. Generally, unless
there are specific problems, only a short review is necessary before flights
four and five. However, if there are problems the time to correct them
is on the ground. On the fourth flight it is essential that the student
understand clearly the behavior of the magnetic compass, and he should
be given several problems on the ground to make sure of this. Cover any jj
difficulties encountered in the second and third flights to avoid a repe-
tition of them. Take as long as necessary to make certain all points of
the procedure are clear before starting the flight.
FLIGHT: APPROXIMATELY 48 MINUTES
Normally, practice will consist of problems of a similar nature to
the cross-country problem given in period 3. Assuming no difficulties, the
student should be able to do about five of these in the allotted time, each
taking from 4 to 12 minutes, averaging probably around 7 minutes. If any
part of the procedure presents difficulty, take care of it immediately.
At some time during the fourth or fifth flight, the instructor should
permit the student to make a let-down to an altitude of 50 to 100 feet.
This is to show him that in an extreme emergency he could make a con-
trolled let-down under the most adverse ceilings and visibilities. It should
be pointed out that this requires a calculated risk involving TV towers,
etc., but even if the airplane crashes, if at the time of contact it was in
a gradual descent, the (fiances of the occupants living are better than
tin \ would have been with no control.
At least once during the fourth flight the instructor should let the
student do a complete problem without any "coaching." This serves a
dual purpose: It gives both the student and the instructor an appraisal
of the student's progress and forces the student to think for himself. Do
this at least twice on the fifth flight. The instructor will make a notation
of any mistakes or aids that he can offer to the student on the com-
pletion of the problem.
Purpose: (1) To test the student's ability to do the self-saving procedure.
(2) To allow the student to test any innovations of his own invention.
(3) To emphasize the "get out" rather than the "get through" aspect of
PREFLIGHT DISCUSSION: APPROXIMATELY 5 MINUTES
"This is the last period of the curriculum. It will be a flight test con-
sisting of three separate problems similar to the ones we have been prac-
ticing. The first problem will be a cross-country flight to Memphis. When
we are well clear of the airport and at cruising altitude we'll encounter
'instruments.' The problem is yours alone. The only information you'll
be given is when to start, weather information to help you to decide
whether and how far to let down, and when you are through with the
problem. You'll get a look at the point where you start the problem be-
fore you put on the goggles so that you will be able to realize your
progress after removing the goggles at the conclusion of the problem.
The other two simulated instrument problems will be similar and you'll
get the necessary information for them in the air."
FLIGHT: APPROXIMATELY 42 MINUTES
It is the instructor's duty to be sure that the student is absolutely clear
on his part in the test. During the process of teaching, the student some-
times becomes dependent on the instructor for cues and help. Any tend-
ency toward this should be completely dispelled before giving the student
the final problems. Give him the problem, show him his geographical
starting point, and start the simulated instrument encounter. If you want
him to make a let-down, then give him the weather information that
would lead to that logical conclusion. 20 After he has successfully com-
pleted his turn and is back approximately 3 to 5 miles beyond his starting
20 This is to simulate the type of situation where he could listen to a weather
equence on the radio or communicate with a CAA Communications station.
point, have the student lift his goggles and observe his location. Leave
the student "on instruments" until he either breaks out of the "weather,"
gets into a dangerous flight attitude, or spends too long trying to get back.
The instructor should give no coaching. He should make the experience
as realistic as possible.
After successfully completing the 180-degree procedure three times,
the student should be given the opportunity to have another simulated
instrument encounter during which he has a "free rein," that is, ex-
plain to him that the curriculum is over but that he can have one more
try at a simulated instrument flight. He must still do his best to get out
of the bad weather, but he can use any means he wishes to do so. He can
use the 180-degree procedure, modify it if he desires, or use a method
of his own.
The purpose of the "free rein" instrument try is to convince the stu-
dent that the practiced procedure is better than an impromptu and im-
provised system of his own. The student may have enough confidence in
the self-saving system so that he will not want to try anything else;
he knows that the 180-degree turn procedure will work. However, he may
want to help the oscillations along by controlling the elevators. In that
case, sooner or later, the student will give just the opposite stick pres-
sure needed and actually aggravate the oscillations.
The student must understand that the 180-degree turn system is a
procedure to use only in case of emergency and in order to get out of
the instrument flight conditions. This point can be brought vividly to the
student's attention by asking him to fly, under simulated instrument
conditions, to a certain airport. He must have the same equipment that
a qualified pilot would need to get there on instruments. For example,
at the University of Illinois the student might be requested to take the
instructor to Chanute Air Force Base. The essentials are there : RAN — a
low-frequency radio range station, a low-frequency receiver in the plane,
and of course the primary instruments necessary for instrument flight.
What the instructor asks the student to do will depend on the equip-
ment in the plane. If the plane is equipped with Omni or ADF he might
ask the student to take him to the nearest airport with navigational
facilities. The whole point is to prove to the student that the 180-degree
procedure can get him out of trouble but that it is not sufficient to get
him through to a destination by instrument flight. The student at the
completion of the course should be sufficiently impressed with the prob-
lems of instrument flight that he will avoid instrument flight conditions
Until properly trained.
POSTFLIGHT DISCUSSION: APPROXIMATELY 13 MINUTES
"There are several factors concerning the 180-degree course that
should be called to your attention now that you have completed the cur-
riculum. While you have demonstrated your proficiency in doing the
procedure today, there is some doubt that you will still be able to do it
six months from now. In order to keep an instrument rating current a
pilot must practice six hours every six months, or an average of one hour
a month. Practice this system occasionally. You could do this on a cross-
country flight with little sacrifice of time. However, in order to remain
proficient on the 180-degree procedure it is essential that some kind of an
instrument flight simulating setup be used in your airplane. It has been
proved that even the slightest cue outside of the aircraft is enough to
enable the pilot to control the attitude of the plane.
"The problem of the transition from VFR to instrument flight was
clearly defined for us during the course. That is, you had no trouble in
making the decision to use the emergency 180-degree procedure. Once
you lowered the goggles you couldn't see anything outside. Also, you were
mentally prepared for an instrument flight; you knew that you were
going to practice the procedure when you got into the airplane. This is
not true for the emergency when you inadvertently find yourself 'on in-
struments'. If you had any inkling that your flight was going to encounter
instrument flight conditions you wouldn't have taken off in the first place.
When to stop trying to see the ground and admit that you no longer
have outside references by which to control the attitude of the aircraft
is a very real problem. Even qualified instrument pilots have been known
i to get into trouble by not making a timely transition from contact to in-
strument flight. Occasional glimpses of the ground are not enough to
maintain successful contact flight. As soon as there is any doubt about
whether you can successfully continue your flight on visual flight rules
you should turn back, land, or make some decision that will keep you
out of trouble. If you do find yourself in instrument flight conditions, then
act immediately. Go through the self-saving procedure. Hesitating, flying
half contact and half instruments, is extremely dangerous.
"Panic is a situation that is impossible to simulate. You know that an
instructor isn't going to let you get into any attitude or flight condition
from which he can't recover. Panic in this case isn't a factor. But it can
be a very real factor should you find yourself in an actual situation where
you have to control the aircraft solely by reference to instruments. Having
in mind a positive course of action such as the self-saving system is a
definite deterrent to panic. Practicing it until it becomes automatic, and
reviewing it often, may sometime save your life."
WEIGHT AND BALANCE FOR THE BONANZA USED IN THIS EXPERIMENT
Critical Rearward CG Check (Full Fuel)
* Aircraft W.E.
Oil (2'/2 gal.)
Fuel (40 gal.)
= 84.16" Aft of datum
Rearward CG at 2700 lbs. is ( + 84.4)
* Includes unuseable fuel 6 lbs. at (+79) and unuseable oil 3 lbs. at ( + 37).
FOR WEIGHT AND BALANCE AND CG RANGE SEE CAA SPECIFICATION A777 Rev. 22.
Critical Rearward CG after 1 Vz hrs. Flight with 13.33 gal. of Fuel Consumed
ITEM WEIGHT ARM + MOMENTS
* Aircraft W.E.
Oil (2'/ 2 gal.)
Fuel (26 2 / 3 gal.)
= 84.43" Aft of datum
Rearward CG limit at 2620 lbs. is ( + 84.4)
+ Includes unuseable fuel 6 lbs. at ( + 79) and unuseable oil 3 lbs. at ( + 37).
FOR WEIGHT AND BALANCE AND CG RANGE SEE CAA SPECIFICATION A777 Rev. 22.
Representative Case Records
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I. Accident Facts, 1953 Edition, Chicago: National Safety Council, 1953
2 iir Navigation, TM 1-205, Washington: The War Department, 1940
3. All-Weather Flight Manual, NavAer 00-80T-37, The Office of the Chief of
Naval Operations, U. S. Navy, 1950
4. C.A.A. Statistical Handbook of Civil Aviation 1953, Washington: U. S.
Government Printing Office, 1953
5. Principles of Flying, U. S. Navy, New York & London: McGraw-Hill Book
Co., Inc., 1943
6. Flight Thru Instruments, Aviation Training Division, U. S. Navy, 1945
7. Instrument Flying, Techniques & Procedures, AFM 51-37, Department of
the Air Force, 1951
8. Instrument Flying, Techniques & Procedures, Instructor's Manual, AFM
51-36, Department of the Air Force, 1951
9. Theory of Instrument Flying, AFM 51-38, Department of the Air Force,
10 Draper, C. S., Cook, W. H., McKay, Walter, "Northerly Turning Error of
the Magnetic Compass for Aircraft," Journal of Aeronautical Science,
vol. 5, 1938, 345-354
II. Mitchell, C. O., "Leave the Wheel Alone," New York: Air Facts, May, 1952
12. Roscoe, Stanley N., "Flight By Periscope," Urbana: The University of
Illinois, Aeronautics Bulletin Number 9, 1951
13 Roscoe, S. N., and Williams, A. C, Jr., "Pilot performance in instrument
flight as a function of the extent and distribution of visible horizon,"
Port Washington, New York: U. S. Navy, Special Devices Center,
Technical Report SDC 71-16-3, June, 1949
11. Soderlind, Paul A., "Instrument Lifesaver for the Contact Pilot," New
York: Air Facts, September, 1951
THE INSTITUTE OF AVIATION, established in 1945 as the Institute of
Aeronautics, is operated as the administrative agency responsible for the
fostering and correlation of the educational and research activities related
to aviation in all parts of the University. Other functions include aca-
demic instruction, flight training, management of the University of
Illinois Airport, and aeronautical research.
In connection with the latter function, the Institute issues two types
of publications . . . first, a group of reports on research results, and
second, a series of bulletins on aviation subjects of an extension-service
nature to the citizens of the State.
The following publications have been issued:
BULLETIN ONE: Municipal Airport Management, Leslie A. Bryan, 1947.
(Out of print)
bulletin TWO: Landscape Planting for Airports, Florence B. Robinson,
bulletin THREE: Labor Relations in the Air Transport Industry Under
the Amended Railway Labor Act, E. B. McNatt, 1948.
BULLETIN FOUR: Airport Zoning, J. Nelson Young, 1948. (Out of print)
bulletin FIVE: Evaluation of the School Link as an Aid in Primary
Flight Instruction, A. C. Williams, Jr. and Ralph E.
bulletin SIX: Lightplane Tires on Turf and Concrete, Leslie A. Bryan,
bulletin SEVEN: Light Aircraft Operating Costs, Leslie A. Bryan, 1949.
bulletin EIGHT: Evaluation of the School Link and Special Methods of
Instruction in a Ten-Hour Private Pilot Flight-Training
Program, Ralph E. Flexman, William G. Matheny, and
Edward L. Brown, 1950. (Out of print)
bulletin NINE: Flight by Periscope : I. Performing an Instrument Flight
Pattern; the Influence of Screen Size and Image Magni-
fication, Stanley N. Roscoe, 1951.
bulletin TEN: Operating Costs of a Light Aircraft Fleet, Leslie A.
bulletin eleven: 180-Degree Turn Experiment, Leslie A. Bryan, Jesse W.
Stonecipher, and Karl Aron, 1954.
Publications of the Institute of Aviation will be sent free of charge